ethereum

问题 I'm creating my first Ethereum contract with truffle. I want the web application to be usable without MetaMask so I was wondering if it is a good idea to run my own private node and to connect from the frontend like this: this.web3 = new Web3(new Web3.providers.HttpProvider('http://my-public-ip:8545')); Are there any security risks with this approach ? 回答1: I'm answering my own question because it seems that a lot of people are doinig the same mistake that I did and lose their ether ! I did

问题 I just got chance to work on Ethereum, block-chain based platform. But I don't have a clear idea in which scenarios this is used, any real life use of this.Could anybody help me understand blockchain based platform and its real life uses? 回答1: Welcome to blockchain world.Don't get demotivated, Blockchain area is relatively new & hard to find good tutorials.I also started learning blockchain related technologies a month ago & I would like to share some ideas about Blockchain & Ethereum.Since

问题 I'm in the process of creating an Ethereum DApp. The DApp consists of users who have associated data like email, name, and a profile picture. I would like to store the contents of the user within IPFS as a JSON object and reference this on chain using the IPFS hash. How could I go about associating this data with a particular user? In the sense, that subsequent interactions with the DApp connect the user with the data stored in IPFS. Is this done using the users account hash with a password

问题 pragma solidity ^0.5.3; contract Inbox { string public message; function Inbox(string initialMessage) public { message = initialMessage; } function setMessage(string newMessage) public { message = newMessage; } function getMessage() public view returns (string) { return getMessage; } } Error : browser/Untitled.sol:3:1: ParserError: Source file requires different compiler version (current compiler is 0.5.3-nightly.2019.1.15+commit.6146c59a.Emscripten.clang - note that nightly builds are

问题 I started learning ethereum and web3js and noticed some functions on Web3js are asynchronous. What i want to achieve is get the account balance of a wallet and use the data for something else. My code below function getAccountBalance2(address){ var wei, balance //address = document.getElementById("addy").value return new Promise(function(resolve, reject){ web3.eth.getBalance(address, function(error, wei){ if(error){ console.log("Error with address"); }else{ var balance = web3.fromWei(wei,

问题 I am following this tutorial to run Ethereum crawler using Docker on window 10 using docker after executing $ MYSQL_DATA_PATH="$HOME/indexer-data/mysql" GETH_DATA_PATH="$HOME/indexer-data/geth"docker-compose up in this line i got error 409 Client Error: Conflict for url: http+docker://localnpipe/v1.25/containers/ee2b46142bae704d4963853e22a77ba896a8f841120ecf5ac97befca91847672/attach?logs=0&stdout=1&stderr=1&stream=1 During handling of the above exception, another exception occurred: Traceback

问题 I am designing a solution for an ethereum smart contract that does bidding . The use-case includes reserving a name eg. "myName" and assigning to an address. And then, people can bid for that name (in this case myName). There can be multiple such biddings happening for multiple names . struct Bid { address bidOwner; uint bidAmount; bytes32 nameEntity; } mapping(bytes32 => Bid[]) highestBidder; So, as you can see above, Bid struct holds data for one bidder, similarly, the key (eg. myName) in

问题 This is a follow up to these threads: How to set state of a react component with a specific item from a returned json object? How to return json data to a react state? I am using web3 to sign a transaction on Ethereum , which then sends a json object with transaction data. The json takes at least 30 seconds to return. I am trying to console.log() the data with the following code: axios.post( "http://compute.amazonaws.com:3000/users", { value: "value", fileName: "fileName", hash: "hash" } )

问题 I've just finished setting up a Ethereum Stack using the AWS Blockchain Template according to the docs here I've sshed to the EC2 instance (bastion host) from my local machine and I can hit the EthStats URL via curl from the bastion host but when I try to go tot he url from chrome, it gives 'This site can’t be reached' error, even though I've setup a FireProxy as per the instructions in the docs. How do I connect to the Ethereum URLs given in outputs of my Ethereum stack in the AWS

问题 when the currentBlock becomes close to the highestBlock, it stop growing, and the highestBlock begin to grow. A while later, the currentBlock begin growing again. I run geth with command geth --rinkeby --fast . the highestBlock on my geth is very close to the actual number on https://www.rinkeby.io/#faucet. > eth.syncing { currentBlock: 2401750, highestBlock: 2401826, knownStates: 14219701, pulledStates: 14205841, startingBlock: 2401554 } > eth.blockNumber 0 logs below, seems normal: INFO [06